books.google.bg - With the transfer of German units to the western front in the spring of 1918, the position of the Central Powers on the Macedonian front worsened. Materiel became scarce and morale among the Bulgarian forces deteriorated. The Entente Command perceived in Macedonia an excellent opportunity to apply additional...https://books.google.bg/books/about/Balkan_Breakthrough.html?hl=bg&id=lVJ3BwKa9wMC&utm_source=gb-gplus-shareBalkan Breakthrough